In a cognitive network, as it may be assumed that network setting, such as frequency, radio modulation method, and access scheme are dynamically changed in each terminal, it is necessary for each terminal to include a mechanism to determine desirable network setting. This may be achieved, for example, by a mechanism in which each terminal receives information provided through a specific radio channel called “cognitive pilot channel”, which is shared among all terminals so that each terminal may determine own network setting based on this information.
A method of changing a radio system without accessing the cognitive pilot channel is disclosed in Patent Literature 1. In this method, a part of an existing method's radio frame includes information related to availability of other method's radio systems so that each terminal having received such information may select, from among a plurality of radio systems, a system to be used.